Search

For large-scale and long-distance distributed systems, this paper proposes a systematical multiparadigm approach to develop the simple network management protocol (SNMP) agents for remote monitoring and control. The standard unified modeling language (UML) is adopted for modeling the system, and then the Petri-net model is applied to achieve both qualitative and quantitative analyses for the system's dynamic behavior. In real applications, the present design can be further implemented with Java and ladder diagrams on programmable logic controllers (PLC). The developed system has been used successfully in a mobile switching center (MSC) of Taiwan Cellular Corporation for the remote monitoring and control, through the Internet, of its environmental conditions, including the temperature, humidity, power, and security, with a total of 316 sensors and 140 actuators.

In modern manufacturing, the design of multi-axis motion controllers for high-speed/high-precision and complex machining is becoming more critical. In the past, controllers for each axis were, in general, designed individually to obtain desirable tracking accuracy. Although some advanced motion control algorithms have been developed recently, they are mostly applicable to single-axis or biaxial systems. In particular, the design of two-axis integrated control, which includes: 1) feedback loops; 2) feedforward loops; and 3) the cross-coupled control (CCC), achieves significantly improved performance. However, its applications are limited to basic linear and circular contour commands for two-axis systems only. In this paper, system analysis for the multi-axis integrated control structure is proposed in order to achieve tracking and contouring accuracy simultaneously. With the derived contouring error transfer function (CETF), the integrated control design for multi-axis motion systems can be formulated simply as a single-input-single-output (SISO) design. Thus, a robust design with desirable performance for multi-axis motion systems can then be achieved straightforwardly. Moreover, by estimating the contouring error vector, the proposed multi-axis integrated control can be widely applied to general contour commands. Experimental results on a three-axis CNC machining center indicate that both tracking and contouring accuracy are simultaneously improved by applying the proposed control design.

Recently, feedforward controllers like zero phase error tracking controllers (ZPETC) and cross-coupled controllers (CCC) have been developed to effectively reduce tracking error and contouring error, respectively. This paper proposes an integrated controller which combines ZPETC and CCC to achieve both tracking and contouring accuracy. Furthermore, studies indicate that ZPETC and CCC can be designed separately in the present integrated control design. In the provided experimental setup with a servo table, an optimal ZPETC and a robust CCC based on the contouring error transfer function (CETF) were designed to achieve desirable frequency responses and stability. Experimental results show that the proposed integrated controller renders significantly improved accuracy in both tracking and contouring.

This paper describes the implementation of an integrated control/diagnostic system for an advanced hard disk drive (HDD) servo system. An observer-based state feedback control design with the pole placement technique has been successfully applied to achieve a bandwidth of 688 Hz, which is quite satisfactory at a 4.5 kHz sampling frequency. Experimental results indicate, however, that the performance of this high precision, high-order control system deteriorates seriously when faults occur. Therefore, a fault identification filter (FIDF) was adopted for fault detection of sensor and actuator failures and accommodation of the actuator failure. In cases where either sensor or actuator fault occurs, experimental results indicate that to maintain high precision and control performance for the HDD system, DSP implementation of the high-order integrated control/diagnostic system is necessary. >